JP4503129B2 - Manufacturing method of hollow parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a hollow part and a hollow part, and more specifically,
The present invention relates to a press working technique for forming a hollow part having a hollow portion therein.
[0002]
[Prior art]
[0003]
For example, for automotive parts such as automobile engine camshafts and transmission countershafts, hollow parts whose interiors are hollow due to demands for weight reduction or requests to share the lubricating oil supply path to each part There is something that is produced as.
[0004]
In manufacturing these hollow parts, (a) first, a solid metal material having a predetermined outer shape is formed by cold forging, and then the metal material is subjected to hole processing to make the inside hollow. A method of closing the hollow hole with a lid material, (b) a method of forming a sheet metal into a hollow part of a predetermined shape by drawing, or (c) after forming a hollow pipe material into a predetermined outer shape by a predetermined processing machine, For example, a method of closing the end with a lid has been adopted.
[0005]
[Problems to be solved by the invention]
However, any of these conventional manufacturing methods has the following problems, and improvements have been demanded.
[0006]
(a) About cold forging a solid metal material:
i) The molding load during cold forging is very large.
That is, in the case of a solid metal material, deformation resistance at the time of plastic deformation due to internal friction of the metal is large, which requires a large press machine.
[0007]
ii) Since drilling after cold forging and subsequent clogging are required, the number of processes is large and the manufacturing cost is relatively high.
[0008]
(b) About drawing method of sheet metal:
In the method of forming a sheet metal into a hollow part having a predetermined shape by drawing, the first drawing rate is 55% to 50% of the blank diameter, and the drawing rate after the second drawing is the same as that of the first drawn product. 75% to 80% of the outer diameter.
[0009]
For example, when the outer diameter of the first drawn product is 35 mm and the outer diameter is to be further reduced, the outer diameter of the second drawn product that can be drawn is 26.3 mm. Therefore, a total of three steps are required to reduce the outer diameter of 35 mm to 17.5 mm with the sheet metal diaphragm.
[0010]
In addition, when hollow parts are manufactured by this method, there is a problem that the thickness of the finished product varies and is not uniform.
[0011]
(c) About molding from hollow pipe material:
In the method of forming from a hollow pipe material, the permissible outer diameter reduction rate is 10 to 15%, which is lower than the above-described drawing by the sheet metal press.
[0012]
For example, when a hollow pipe material having an outer diameter of 35 mm is used, if the first drawing is 30 mm in diameter and the second drawing is 26 mm in diameter, the outer diameter of the final product is 17.5 mm. In total, 5 steps are required.
[0013]
The present invention has been made in view of such conventional problems, and the main purpose thereof is a lightweight hollow part having a hollow portion inside, with a small number of steps without requiring drilling, In addition, the present invention provides a press working technique that can be manufactured with a small molding load.
[0014]
[Means for Solving the Problems]
In order to achieve this object, the method for manufacturing a hollow part according to the present invention forms a solid molding material by filling an incompressible fluid into a hollow interior of a hollow metal material, and presses the solid molding material. After pressing into a predetermined outer shape by pressing with a machine, the incompressible fluid inside the hollow is discharged, and the solid molding material is inserted into the hollow inside from the opening of the hollow metal material. After the fluid is filled, the opening is closed and sealed, and the pressing by the press machine has an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part of the molding die. By putting the solid molding material into the cavity and pressurizing the solid molding material that has been blocked by a punch so that the opening is further blocked from above, the high liquid-tightness of the blocked portion is increased. Secure One, material flow mechanisms of the actual forming material in the above is uniformly pressed hollow interior of the side wall to the outside, the outer peripheral surface thereof, characterized in that so as to faithfully along the inner peripheral molding surface of the cavity.
[0015]
As a preferred embodiment,
(1) Material forming step of forming a solid molding material by filling a hollow metal material with an incompressible fluid inside the hollow interior (2) Pressing the solid molding material with a press to form a predetermined outer shape A part molding process for molding a solid part , and (3) a finishing process for discharging the incompressible fluid inside the solid part into a hollow part,
In the material forming step, the solid forming material is formed by filling the incompressible fluid from the opening of the hollow metal material into the hollow interior, and then closing and sealing the opening,
In the part molding step, the solid molding material is introduced into a cavity having an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part of the molding die, and the medium is closed by the punch of the press machine. By applying pressure so that the opening of the actual molding material is further blocked from above, the material flow mechanism of the solid molding material allows the side wall of the hollow interior to outward while ensuring high liquid-tightness of the closed portion. The solid part is molded by pressing evenly so that its outer peripheral surface is faithfully aligned with the inner peripheral molding surface of the cavity.
[0016]
As the fluid, an incompressible liquid such as water or oil is preferably used.
[0017]
In the present invention, a solid molding material is formed by filling an incompressible fluid into the hollow interior of the hollow metal material, and the solid molding material is pressed into a predetermined outer shape, It is possible to perform plastic working similar to that of a conventional solid body.
[0018]
In other words, the hollow metal material as the molding material of the present invention is filled with an incompressible fluid inside the hollow, so that the material flow mechanism of the hollow metal material during press molding is the same as that of the solid body. And the fluid which is an internal filler is much rich in fluidity | liquidity compared with solids, such as a metal, from the characteristic.
[0019]
Therefore, the molding material can be used for billets for upsetting, intermediate shaft upsetting, extrusion, compound processing, and closed forging, as well as conventional solid plastic processing. It is much better than a general solid body, and a press with a much smaller pressing force compared to conventional forging can be realized.
[0020]
Embodiment
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0021]
A method for manufacturing a hollow part according to the present invention is shown in FIGS. 1 to 4. For example, a hollow part that is required to be reduced in weight, such as an automobile engine camshaft and a transmission countershaft. This is an optimum manufacturing method for manufacturing W. Hereinafter, a case where a camshaft of an automobile engine is manufactured will be described as a specific example.
[0022]
The basic structure of the manufacturing method of the present invention is as follows. First, a fluid 3 is filled in a hollow interior 2 of a hollow metal material 1 as shown in FIG. 1A, and a molding material (as shown in FIG. Billet) 4 is formed, and then the molding material 4 is pressurized as shown in FIG. 1C or FIG. It is formed into an outer shape, and finally, the incompressible fluid 3 in the hollow interior 2 of this molded product is discharged to obtain a finished product W. In addition, as the fluid 3, an incompressible fluid is used, and for example, an incompressible liquid such as water or oil is preferably used.
[0023]
The manufacturing method of the illustrated embodiment specifically includes the following steps.
[0024]
(1) Hollow metal material molding process :
The hollow metal raw material forming step includes various methods as described below, and an optimum method is selected and adopted from these methods according to the purpose.
[0025]
(A) After forming the hollow member 6 having the bottom 6a from the metal round bar 5 as shown in FIG. 2 (a) by the cold forging method (see FIG. 2 (b)), the open end 6b is The end surface is trimmed by cutting (see FIG. 2 (c)), and finally, a lid member 7 as a closing member is closed and welded to the upper opening to form a hollow metal material 1 having a predetermined shape (FIG. 2). (See (d)). The lid member 7 has an injection hole 7a for injecting the fluid 3.
[0026]
Instead of closing the upper opening of the hollow member 6 with the lid member 7, as shown in FIG. 2 (e), a plate-like seal 15 made of a plastic sheet may be attached and closed as a closing member. In practice, the plate-like seal 15 is pasted after the incompressible fluid 3 is filled in the hollow interior 2 of the hollow metal material 1 as described later.
[0027]
(b) After squeezing one end 8a of the metal tube member 8 as shown in FIG. 3 (a) by the swing rotational molding method or the eccentric rotational molding method (see FIG. 3 (b)), the rotational molding is further performed. The end 8a is squeezed and closed by the method (see FIG. 3B). Subsequently, similarly to the above (a), the lid 7 is closed by welding or the like at the opening at the other end, and is formed into a hollow metal material 1 having a predetermined shape (see FIG. 3 (d)). As in the case of the above (a), the plate-like seal 15 may be attached and closed instead of the lid member 7.
[0028]
When both ends are closed as in the hollow metal material 1 of this embodiment, or when only one end is an open end, any of the above methods (a) and (b) may be used.
[0029]
When only one end is an open end, the process of FIG. 2 (e) or FIG. 3 (e) is adopted instead of the process of FIG. 2 (d) or FIG. 3 (d).
[0030]
Moreover, although not shown in figure, about the hollow metal raw material 1 for components W by which both ends are open ends, in the case of a standard size and a standard material, the metal tube material 8 is cut into a predetermined length. In the case of a special size and special material, as shown in (a) above, after forming the hollow member 6 having the bottom 6a from the metal round bar 5 by the cold forging method, 6a is punched.
[0031]
In the case of the component W having both ends open as described above, although not shown, the plate-like seal 15 used in the process of FIG. 2 (e) or FIG. 3 (e) described above is replaced with a metal tube material. 8 or the other opening of the hollow member 6 is used to close these openings. In this case, the blockage of the other opening is applied to the hollow interior 2 before the incompressible fluid 3 is filled, and then the fluid 3 is filled.
[0032]
(2) Material molding process :
After filling the hollow interior 2 of the hollow metal material 1 made as described above with the incompressible fluid 3, the opening of the hollow metal material 1 is closed and sealed (encapsulated), and the molding material 4 is formed. Mold. In this case, it is desirable that the air in the hollow interior 2 is completely removed and the interior is filled with the fluid 3. In the present embodiment, oil is used as the fluid 3.
[0033]
As shown in FIG. 2 (d) or FIG. 3 (d), when the upper opening of the hollow metal material 1 is closed by the lid member 7, it is not compressed from the injection hole 7a provided in the lid member 7. After filling the permeable fluid 3, the injection hole 7 a is closed, while the upper opening of the hollow metal material 1 has a plate-like seal as shown in FIG. 2 (e) or 3 (e). In the case of being closed by 15, after filling the incompressible fluid 3 from the upper opening of the hollow metal material 1, this upper opening is closed by sticking the plate-like seal 15.
[0034]
The molding material 4 molded as described above is a solid molding material having the fluid 3 as a constituent material.
[0035]
(3) Parts molding process :
The component forming step is performed using a press machine provided with a split structure molding die (molding die) 10 and a pair of upper and lower punches 11 and 12.
[0036]
The molding die 10 is composed of a pair of split molds 10a and 10b divided into left and right halves, and these split molds 10a and 10b are structured to open and close in the horizontal direction by a driving device (not shown).
[0037]
Further, the upper and lower punches 11 and 12 constitute the upper and lower walls of the cavity 13 in a state in which the split dies 10a and 10b are closed, respectively, and are configured to be pressed in the vertical direction by a driving device (not shown). Yes.
[0038]
The cavity 13 of the mold 10 has an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part W. On the other hand, as shown in FIG. 4 (b), the upper and lower punches 11 and 12 slide in the cavity 13 closely in the vertical direction to pressurize the upper and lower surfaces of the molding material 4.
[0039]
Then, as shown in FIG. 4A, after the molding material 4 is put into the cavity 13 with the molding die 10 (10a, 10b) closed, as shown in FIG. The punches 11 and 12 are driven. Thus, the molding material 4 is pressed from above and below, that is, from both the axial direction of the molding material 4 by the upper and lower punches 11 and 12, and the outer peripheral surface thereof is molded along the inner peripheral molding surface of the cavity 13. Thus, the solid part W ′ having the final outer peripheral shape of the hollow part W is obtained.
[0040]
That is, as shown in FIG. 4B, the upper and lower punches 11 and 12 press the solid molding material 4 having the fluid 3 as a constituent material from above and below, and the flat lower surface 11a (see FIG. 5 (a) and (b)) pressurizes the molding material 4 closed by the lid material 7 so that the opening is further closed from above, thereby further increasing the liquid-tightness of this portion. As a result, the flow mechanism of the material (fluid) 3 of the solid part W ′ at this time uniformly presses the side wall of the hollow interior 2 of the molding material 4 outward by the applied pressure in the vertical direction. Te, so that its outer peripheral surface to closely along the inner peripheral molding surface of the cavity 13 (to press molding).
[0041]
When the solid part W ′ is formed, the upper and lower punches 11 and 12 are moved up and down in the vertical direction, and the split dies 10a and 10b are opened in the horizontal direction, and the solid part W ′ is taken out.
[0042]
2 (e) or 3 (e), when the molding material 4 (hollow metal material 1) is closed by the plate-like seal 15, the molding material 4 is put into the cavity 11. Thereafter, as shown in FIG. 5B, when the upper and lower punches 11 and 12 (the lower punch 12 is not shown) are driven, the plate seal 15 is raised above the hollow metal material 1 by the flat lower surface 11a of the upper punch 11. The hollow metal material 1 is further brought into close contact with liquid tightness, and the hollow metal material 1 is placed in a solid molding material state.
[0043]
Further, the pressurizing force of the upper and lower punches 11 and 12 acts, and the hollow metal material 1 is pressurized from the vertical direction (both in the axial direction of the molding material 4) while increasing the liquid tightness by the plate-like seal 15. The outer peripheral surface is formed so as to be along the inner peripheral molding surface of the cavity 11, so that the solid part W ′ having the final outer peripheral shape of the hollow part W is obtained.
[0044]
In this case, as shown in FIG. 6, by providing the annular protrusion 16 on the flat lower surface 11a of the upper punch 11 over the entire circumference, higher liquid tightness is ensured. That is, as shown in FIG. 6 (b), when the upper and lower punches 11 and 12 are driven, the plate-like seal 15 bites into the hollow metal material 1 by the annular protrusion 16 of the upper punch 11, and the liquid-tightness of this part is high. Therefore, the hollow metal material 1 is placed in a solid molding material state. Other configurations are the same as those in FIG.
[0045]
In the illustrated embodiment, the molding material 4 is pressed from both sides in the axial direction by the upper and lower punches 11, 12, but depending on the purpose, the molding material 4 is pressed in the axial direction by the upper punch 11. You may make it pressurize from above. Further, in addition to the pressurization in the axial direction by the upper and lower punches 11 and 12, by the closing operation of the split molds 10a and 10b, the pressurization is also performed from the direction intersecting the axial direction (the orthogonal direction in the illustrated embodiment). May be.
[0046]
(4) Finishing process :
The finishing step is a step of discharging the fluid 3 inside the solid part W ′. Specifically, the sealing material (not shown) that closes the injection hole 7a of the lid member 7 is once removed and injected. The fluid 3 inside the hollow is caused to flow out from the hole 7a, or the plate-like seal 15 is removed, and the fluid 3 inside the hollow is caused to flow out to form a hollow part W that is a final product.
[0047]
Therefore, in the manufacturing method configured as described above, the hollow material 2 of the hollow metal material 1 is filled with the incompressible fluid 3 to form the molding material 4 (hollow metal material 1). The molding material 4 is pressed to be molded into a predetermined outer shape. That is, the hollow metal material 4 as the molding material at this time is filled with the incompressible fluid 3 in the hollow interior 2 so that the material flow mechanism of the hollow metal material 1 during press molding is solid. It will be the same as that. As a result, the fluid 3 is much more fluid than the solids such as metal due to its characteristics, and the pressure applied from the upper and lower punches 11 and 12 is applied to the side wall of the hollow metal material 4 via the fluid 3. Will be applied uniformly.
[0048]
Therefore, the molding material 4 can be used for billets for upsetting, shaft intermediate portion upsetting, extrusion, compound processing and closed forging, as well as conventional solid plastic processing, and its moldability is also high. It is much better than a general solid body, and a press with a much smaller pressing force compared to conventional forging can be realized.
[0049]
The above-described embodiments are merely for illustrating preferred embodiments of the present invention, and the present invention should not be construed as being limited thereto, and various design changes can be made within the scope of the present invention. is there. For example, the following modifications are possible.
[0050]
(1) In the illustrated embodiment, the molding material 4 is made into a completely sealed state by closing the injection hole 7 a of the lid material 7, but is plastically processed with the injection hole 7 a closed by the upper punch 11. The injection hole 7a may be closed after the molding process of the hollow part W is completed.
[0051]
(2) As described in the above-described embodiment, pressurization of the molding material 4 can be performed not only in the axial direction but also from the side orthogonal or oblique to the axial direction, so-called multidirectional molding. It can also be applied as a billet.
[0052]
(3) In the illustrated embodiment, the cold forging method is used. However, the present invention can also be applied to any method of warm forming and hot forming. . In this case, in consideration of the heating temperature, the optimum conditions should be selected and designed such that the incompressible fluid 3 that is filled and enclosed in the hollow interior 2 is selected. Same as the case.
[0053]
(4) Furthermore, the hollow part W can be molded in the shape shown in FIGS. 7 (a), (b) and FIGS. 8 (a), (b) in addition to the automobile parts shown in the figure. In this case, the hollow part shown in FIGS. 7 (a) and (b) can be molded with the same number of steps as in the above-described embodiment, but as shown in FIGS. 8 (a) and (b). A hollow part having three or more different outer diameters is formed through two or more steps as shown in the figure.
[0054]
【The invention's effect】
As described in detail above, according to the present invention, a solid molding material is formed by filling a hollow metal material with a non-compressible fluid inside the hollow, and the solid molding material is pressed by a press. Then, after forming into a predetermined outer shape, the incompressible fluid inside the hollow is discharged, and the solid molding material is inserted into the hollow inside from the opening of the hollow metal material. Then, the opening is closed and sealed to form, and the pressing by the press machine is performed in the cavity having an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part of the molding die. While charging the solid molding material and pressurizing the solid molding material closed by the punch so as to further block the opening from above, while ensuring the high liquid tightness of the closed part, Solid molding above Since the material flow mechanism of the material uniformly presses the side wall of the hollow inside outward so that the outer peripheral surface is faithfully aligned with the inner peripheral molding surface of the cavity, various effects as listed below can be obtained. The resulting lightweight hollow part having a hollow portion can be manufactured with a small number of steps and with a small molding load without the need for drilling.
[0055]
(1) In the case of reducing possible solid body of forming load large deformation resistance during plastic deformation due to the internal friction of metal, in the case of hollow bodies of the liquid-filled as in the present invention, of course deformation resistance is small Therefore, the molding limit is also increased as compared with the prior art. As a result, it is possible to form a complex shaped part.
[0056]
(2) near net shape, it becomes a possible Niyanetto or net shape for reasons of net shape <br/> above (1).
[0057]
(3) Lightweight possible Since it is made from a hollow body, it is much lighter than comparable parts made of solid material.
[0058]
(4) No need for later drilling of the inside of the part. Since drilling after the cold forging and the subsequent closing process are unnecessary, the number of processes is small and the manufacturing cost is relatively low.
[0059]
(5) Process can be shortened <br/> When making a hollow body by sheet metal drawing, 55% to 50% of the blank diameter in the first drawing, and the first drawing after the second drawing The drawing ratio is 75% to 80% of the outer diameter. For example, when the outer diameter of the first-drawing product is 35 mm and the outer diameter is to be further reduced, the outer diameter of the second-drawing product that can be drawn is 26.3 mm. Therefore, three steps are required to bring the outer diameter of 35 mm to 17.5 mm with the sheet metal diaphragm.
[0060]
Further, when the tube with the open end is squeezed, the reduction rate of the outer diameter per time is 10 to 15%, which is lower than the squeezing by the sheet metal press. For example, a tube having an outer diameter of 35 mm requires five steps to reduce the outer diameter to 30 mm by the first drawing, to 26 mm by the second drawing, and thus to the outer diameter of 17.5 mm.
[0061]
On the other hand, in the case of solid extrusion, if the outer diameter is 35 mm, the diameter can be reduced to about 50%, that is, 17.5 mm. Similarly, a hollow body enclosing a fluid such as the liquid of the present invention can be reduced in diameter at exactly the same rate as in the case of solid extrusion. Therefore, in order to bring the outer diameter of 35 mm to 17.5 mm with the manufacturing method of the present invention, one step is sufficient.
[Brief description of the drawings]
FIG. 1 is a view for explaining a basic configuration of a method for manufacturing a hollow part according to a first embodiment of the present invention.
FIG. 2 is a front cross-sectional view for explaining a step of forming a hollow metal material by a cold forging method in the manufacturing method.
FIG. 3 is a front cross-sectional view for explaining a step of forming a hollow metal material by a swing rotational molding method or an eccentric rotational molding method in the same manufacturing method.
FIG. 4 is a front cross-sectional view for explaining a part forming step in the manufacturing method.
FIG. 5 is a partially enlarged front view for explaining another component forming step in the manufacturing method.
FIG. 6 is a partially enlarged front view for explaining another component molding step in the same manufacturing method.
FIG. 7 is a front sectional view showing a hollow part which is an object of the present invention.
FIG. 8 is a front sectional view showing another hollow part which is also a subject of the present invention.
[Explanation of symbols]
W Hollow part W 'Solid part 1 Hollow metal material 2 Hollow interior 3 Incompressible fluid 4 Molding material 5 Metal round bar 6 Hollow member 7 Lid ( closure member )
8 Metal tube material 10 Mold (mold)
10a, 10b Split mold 11, 12 Punch 13 Cavity 15 Plate seal ( blocking member )

Claims (11)

After filling the hollow interior of the hollow metal material with an incompressible fluid to form a solid molding material, the solid molding material is pressed into a predetermined outer shape by pressing with a press machine, and then the hollow interior To discharge the incompressible fluid of
The solid molding material is formed by filling the incompressible fluid into the hollow interior from the opening of the hollow metal material, and then closing and sealing the opening.
The press working by the press machine is performed by putting the solid molding material into a cavity having an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part of the molding die and closing the solid molding by a punch. By pressurizing the material opening further so as to close it from above, the material flow mechanism of the solid molding material makes the side wall of the hollow interior uniformly outward while ensuring high liquid tightness of this closed part. A method for manufacturing a hollow part, characterized in that the outer peripheral surface is pressed along the inner peripheral molding surface of the cavity faithfully.   The method for producing a hollow part according to claim 1, wherein an incompressible liquid such as water or oil is used as the fluid. (1) Material forming step of forming a solid molding material by filling and filling an incompressible fluid into the hollow inside of the hollow metal material (2) Pressing the solid molding material with a pressing machine to form a predetermined outer shape A part molding process for molding a solid part , and (3) a finishing process for discharging the incompressible fluid inside the solid part into a hollow part,
In the material molding step, the solid molding material is molded by filling the incompressible fluid from the opening of the hollow metal material into the hollow interior, and then closing and sealing the opening.
In the component molding step, the solid molding material is introduced into a cavity having an inner peripheral molding surface corresponding to the final outer peripheral shape of the hollow part of the molding die, and the medium is closed by the punch of the press machine. By applying pressure so that the opening of the actual molding material is further blocked from above, the material flow mechanism of the solid molding material moves the side wall of the hollow interior to the outside while ensuring high liquid-tightness of the closed portion. A method for manufacturing a hollow part, characterized in that the solid part is molded by pressing uniformly and aligning the outer peripheral surface thereof faithfully with the inner peripheral molding surface of the cavity. 4. The method for manufacturing a hollow part according to claim 3, wherein the hollow metal material is a metal round bar formed into a hollow metal material having a predetermined shape by cold forging. The method for manufacturing a hollow part according to claim 3, wherein the hollow metal material is formed into a hollow metal material having a predetermined shape by squeezing an end portion of a metal tube material. The said hollow metal raw material is shape | molded in the hollow metal raw material of predetermined shape by obstruct | occluding the edge part of metal tube materials with a closure member, The manufacturing method of the hollow components of Claim 3 characterized by the above-mentioned. .   The method for producing a hollow part according to any one of claims 3 to 6, wherein an incompressible liquid such as water or oil is used as the fluid.   The solid molding material disposed in a molding die is pressed from one side in the axial direction of the solid molding material to form a solid part having a predetermined outer shape in the component molding step. The method for producing a hollow part according to any one of 3 to 7.   In the component molding step, the solid molding material arranged in a molding die is pressed from two directions in the axial direction of the solid molding material to form a solid component having a predetermined outer shape. Item 8. The method for producing a hollow part according to any one of Items 3 to 7.   In the component molding step, the solid molding material is pressed from the direction intersecting the axial direction in addition to the pressing in the axial direction to form a solid part having a predetermined outer shape. A method for manufacturing a hollow part according to claim 8 or 9.   A hollow part manufactured by the manufacturing method according to claim 1.

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